Fonterra cheese starter cultures date back to 1930s in Palmerston North library
Cheese starters as old as 90 years sit in freezers deep in a Fonterra facility in Palmerston North.
The starters - dairy cultures which form the foundation of cheese making - are on ice at minus 80 degrees celsius at a "cheese library" at the Fonterra Research and Development Centre (FRDC).
A household freezer is about minus 20 C, so freezers at four times lower the temperature are unusual and come at a cost.
Starters still come off the ice and are put to use in the cheese plants today.
Cheese starter cultures are groups of microorganisms which ferment natural milk sugars into lactic acid which then forms the curds and whey with the help of the microbial rennet.
Many of them are the creations of the former Dairy Research Institute, and the library of starters was begun in the 1930s by Dr Hugh Whitehead.
The institute's scientists were world leaders in their field, says James Harnett, executive manager of the Fonterra Microbial Fermentation Unit.
"We are lucky to carry on with their legacy today."
The four large freezers in FRDC's basement hold about 100,000 starters or dairy cultures as they are called, says Harnett.
The centre used to be called the Starter Production Unit, but no-one wants to be known as 'spew' he says, laughing easily.
With almost 30 years at FRDC he knows the place well, the people and staff.
His desk is a mass of books on starters and the viruses that plague them.
Harnett works with six staff in the laboratory checking the microorganisms.
Most of them work with old starters for cheese and many are still used now.
Harnett says the starters are defrosted and they all contain viruses or phage as they are known. They are the plague of starters.
Although phage are harmless to people, they can attack young cells in starters, slowing the cheese making process, or worse still, destroying the entire culture and leading to "dead" vats.
Nobody wants that as a dead vat is a cheese making disaster.
Using their detailed understanding of phage the Fonterra cheesemakers create culture mixes so a phage attack will not render them useless.
Harnett says his staff are extremely good at finding starters that can cope with the viruses.
"They are naturally occurring and one might be good out of hundreds of thousand of microorganisms. The team are really good at finding those few winners."
The starter library is invaluable as new strains are being evolved from older ones as existing cultures become vulnerable to phage attack.
One aspect of the library's history has not survived.
"Up until 1970 strains were named after the director of NZDRI – or at least their initials," Harnett says. "The problem was that if a strain got taken out by a phage, the cheese makers would joke that the director was useless. These days all the strains' identifiers are four digit numbers."
Fonterra is the only major cheese company in the world that makes and supplies its own starters for cheese. Most factories buy them from commercial companies, based in Europe.
Harnett says different starters are used for different cheeses such as cheddar, brie or gouda.
He says commercial starters can be expensive to buy so it is good that Fonterra has its own source.
"We are like a trust in Fonterra making world class starter technology available while achieving the lowest cost of use.
"As a result each of our cheese plants has a starter room. Our Microbial Fermentation Unit provides 150 millilitre pottles of culture and from those the staff at the cheese plant will make 50,000 litres of culture."
Getting the starters out to Fonterra factories is great and most plants grow their own. If a starter is lost by a plant due to phage attack it is lost forever, says Harnett
"Our job is to keep the factories running and a starter is like electricity. You absolutely need it. Without it you might as well go home."
He says hygiene in plants is a major attribute for keeping starters going.
Among the collection at FRDC are the cultures used for the Anchor cheese brand, exported to Britain in the hundreds of thousands of tonnes through to the 1970s.
Thanks to New Zealand dairy scientists, the culture has a built-in maturating process linked to the shipping journey so it arrives in peak condition.
Fonterra considers one of its great cheese strengths is making quality cheddar such as its Mainland brand.
Mining older strains for knowledge is familiar ground for the keepers of the Fonterra collection. That is why they keep 100,000 strains.
"We have developed great skills over the years to keep starters alive during the freezing and storage processes."
Harnett says all cheese, milk powders and butter are about making milk keep well and people have been doing that for centuries.
"In the past, there used to only be butter and cheese in New Zealand, with everything else including skim milk going to the pigs."
Harnett says there used to be hundreds of dairy factories and they all had their own starters. The library is a collection from them.
The cheese starter cultures also have a huge role to play in the cheese's flavour and maturing.
Harnett dreams of getting his hands on cheese from the rations left in Antarctica by Robert Falcon Scott, whose Terra Nova expedition of 1910-13 ended in a well-documented tragedy. Even after more than 100 years, Harnett thinks the cheese has a story that's yet to be told.
"DNA analysis of that cheese would tell us a great deal and we could even recreate the cheese. It is likely that viruses called phage from that era still exist in the cheese as it has been deep frozen for 100 years. The phage has a specific relationship to the microorganisms used in the starter for the cheese. So if we could extract the phage, we could use it as a tool to find the original starters in our collection."
Like Scott's cheese, Fonterra's library is a rarity with today's producers from other companies getting their cultures from external suppliers.
"Our Microbial Fermentation Unit provides 150 ml pottles of culture and from those, the staff in the cheese plant will make as much as 50,000 litres of culture."